Broadly speaking, a medical mechanical ventilator is an automatic machine designed to provide all or part of the work the body must produce to move gas into and out of the lungs. Standard air, oxygen, or a mixture of standard air and oxygen can be provided to the patient at a desired pressure or volume to ensure proper hemodynamic function of the patient. For example, mechanical ventilators can be used in instances of acute lung injury, such as acute respiratory distress syndrome or trauma, apnea with respiratory arrest, chronic obstructive pulmonary disease, acute respiratory acidosis due to paralysis of the diaphragm (e.g., due to Guillain-Barré syndrome, Myasthenia Gravis, spinal cord injury, or the effect of anesthetic and muscle relaxant drugs), neurological disorders, hypoxemia, and hypotension, for example, from sepsis, shock, or congestive heart failure. Given the variety of conditions that can provoke the need for mechanical ventilation, it will be appreciated that the breathing pattern governing the provision of air to the patient will vary significantly with the patient's condition.